Microsoft SQL Server: Heap-based buffer overflow allows remote code execution
Summary
A heap-based buffer overflow in Microsoft SQL Server 2022 (CU27, x64) and SQL Server 2025 (CU10) allows an authorized attacker to execute code over the network. The attacker needs a valid low-privilege database login and the attack complexity is high, so exploitation is not trivial. The CVSS base score is 7.5 (High), and an impact on confidentiality, integrity and availability is possible.
Affected
- SQL Server 2022 for x64-based Systems (CU27): 16.0.4003.1 to before 16.0.4315.2
- SQL Server 2025 CU10: 17.0.4006.0 to before 17.0.5045.3
- Other branches (e.g. SQL Server 2019, 2017, GDR): Unknown.
Fixed in
- SQL Server 2022 CU27: 16.0.4315.2 or later (update package reported as KB 5129300, to be verified)
- SQL Server 2025 CU10: 17.0.5045.3 or later (update package reported as KB 5129299, to be verified)
Workaround
- Unknown. No vendor workaround identified; patching is the stated remedy.
Exploitation
- No confirmed exploitation as of now. CVSS exploit maturity is 'Unproven' and CISA SSVC lists exploitation as none.
- No public proof of concept found.
- NVD status is still 'Awaiting Analysis'.
Our recommendation
- Confirm the build number of every SQL Server instance.
- Apply the fixed cumulative update on affected CU27 and CU10 instances with priority.
- Check the status of older branches against Microsoft's advisory.
- Verify that port 1433 and related services are not reachable from the internet, and restrict access to known application servers.
- Limit sysadmin-level and shared database accounts.
Information from Microsoft (Patch Tuesday November 2026)
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- MSRC Security Update Guide: CVE-2026-88111 msrc.microsoft.com
- CVE Record CVE-2026-88111 www.cve.org
- Strix AI: CVE-2026-88111 www.strix.ai
- NTCompatible: November 2026 Patch Tuesday www.ntcompatible.com
- SQL Server build list sqlserverbuilds.blogspot.com
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 11 Nov 2026, 05:08.
Original description (NVD)
Heap-based buffer overflow in SQL Server allows an authorized attacker to execute code over a network.
NVD references (1)
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
Affected? We can help.
We check whether your systems are affected, install updates and close the gap – continuously with the System Health Checker if you wish.